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Calling sock_orphan inside bh_lock_sock in dccp_close can lead to dead locks. For example, the inet_diag code holds sk_callback_lock without disabling BH. If an inbound packet arrives during that admittedly tiny window, it will cause a dead lock on bh_lock_sock. Another possible path would be through sock_wfree if the network device driver frees the tx skb in process context with BH enabled. We can fix this by moving sock_orphan out of bh_lock_sock. The tricky bit is to work out when we need to destroy the socket ourselves and when it has already been destroyed by someone else. By moving sock_orphan before the release_sock we can solve this problem. This is because as long as we own the socket lock its state cannot change. So we simply record the socket state before the release_sock and then check the state again after we regain the socket lock. If the socket state has transitioned to DCCP_CLOSED in the time being, we know that the socket has been destroyed. Otherwise the socket is still ours to keep. This problem was discoverd by Ingo Molnar using his lock validator. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net> |
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| .. | ||
| ccids | ||
| ackvec.c | ||
| ackvec.h | ||
| ccid.c | ||
| ccid.h | ||
| dccp.h | ||
| diag.c | ||
| feat.c | ||
| feat.h | ||
| input.c | ||
| ipv4.c | ||
| ipv6.c | ||
| ipv6.h | ||
| Kconfig | ||
| Makefile | ||
| minisocks.c | ||
| options.c | ||
| output.c | ||
| proto.c | ||
| sysctl.c | ||
| timer.c | ||